1. Field of the Invention
The present invention relates to a data transfer technique, and particularly relates to a data transfer technique for transferring multimedia data composed of a plurality of files (such as still images, video, audio, text, and the like).
2. Description of the Related Art
Image recording devices that capture images, record video, and so on, such as digital cameras, digital video cameras, DVD recorders, and HDD recorders, have recently become widespread. Furthermore, transferring broadcasted programs recorded using a stationary-type recording device to a handheld device and viewing those programs while in a vehicle is also becoming common.
However, because the handling of multimedia data has always involved heavy processing, there are many cases where mobile phones, handheld music/video players, and the like place limitations on the formats of the multimedia data that they support. For example, there are situations where video data can only be played back if it is of a specific encoding format and of a specific resolution.
Meanwhile, some electronic devices handle a plurality of files as a single piece of multimedia data. When transferring data to such a device in order to use that data in the device, it is also necessary to communicate the relationship of the plurality of files to the device to which the data is being transferred.
In other words, when transferring data to another device in order to use that data in the device, it is not sufficient to simply transfer the data; it is also necessary to transfer the data to the appropriate place, in a file configuration that the electronic device to which the data is being transferred can interpret. Otherwise, the device to which the data has been transferred cannot properly handle the data, and thus the data transfer itself is meaningless.
Object-based communication protocols are becoming common as protocols for transferring multimedia data between electronic devices and information processing devices. PTP (Picture Transfer Protocol) and MTP (Media Transfer Protocol) can be given as examples of object-based communication protocols. A characteristic of object-based communication is that no specialized knowledge is required in order to configure the devices to communicate with one another.
When transferring data to a device that handles a plurality of files as a single piece of multimedia data, it is necessary to communicate the relationship of the plurality of files with object-based communication, too.
Meanwhile, there is a conventional file transfer system that groups a plurality of files together and sequentially transfers the files (see Japanese Patent Laid-Open No. H5-67009).
The conventional image transfer system disclosed in Japanese Patent Laid-Open No. H5-67009 improves the transfer efficiency by grouping a plurality of files together and sequentially transferring the files between data processing apparatuses.
However, the image transfer system disclosed in Japanese Patent Laid-Open No. H5-67009 lacks a scheme for communicating the relationship of the plurality of files transferred as a group to the destination device. Accordingly, the disclosed system cannot be applied as-is when transferring a plurality of files using an object-based protocol such as PTP or MTP to an electronic device that handles that plurality of files as a single piece of multimedia data.